Meaning: 'What' refers to the specific items or things that are being mentioned, in this case, the food purchases of an average Australian family.

Wrong options:

• which: The word 'which' is used to introduce a non-defining relative clause, but it does not fit here as it does not specify the items in the same way as 'what'.
• those: 'Those' refers to specific items that have already been mentioned or are known, but it does not fit the context of introducing a new clause about the average family's purchases.
• that: 'That' is a restrictive relative pronoun, but it does not convey the same level of specificity as 'what' in this context.

Correct answer: following

Explanation: The word 'following' is appropriate here as it indicates the action of adhering to the guidelines. It fits grammatically as a gerund that acts as the subject of the clause, aligning well with the context of the sentence.

Meaning: 'Following' means to adhere to or comply with something, in this case, the dietary guidelines.

Wrong options:

• adhering: While 'adhering' is similar in meaning, it is less commonly used in this context and does not fit as smoothly as 'following'.
• stating: 'Stating' refers to expressing something verbally or in writing, which does not fit the context of acting upon the guidelines.
• sticking: 'Sticking' implies a more casual adherence and does not convey the same level of commitment as 'following'.

Correct answer: rich

Explanation: The word 'rich' is suitable here as it describes diets that are abundant in fruit and vegetables. It fits grammatically as an adjective that modifies 'diets', providing a clear and positive connotation in the context of health benefits.

Meaning: 'Rich' in this context means having a large quantity of something beneficial, specifically fruit and vegetables in diets.

Wrong options:

• separate: 'Separate' does not relate to the context of diet composition and implies division rather than abundance.
• focused: 'Focused' suggests concentration but does not convey the idea of abundance or quantity in relation to diet.
• high: 'High' could imply quantity but is less specific than 'rich' in describing the quality of the diet.

Correct answer: boost

Explanation: The word 'boost' is appropriate as it indicates an increase in mood and mental wellbeing. It fits grammatically as a verb that complements the subject of the sentence, aligning well with the positive outcomes discussed.

Meaning: 'Boost' means to increase or improve something, in this case, mood and mental wellbeing.

Wrong options:

• rise: 'Rise' is typically used as an intransitive verb and does not fit well with the context of actively improving mood.
• exaggerate: 'Exaggerate' implies overstating something, which does not align with the intended meaning of improving mood.
• flourish: 'Flourish' suggests thriving or growing well, but it does not directly convey the idea of improvement in mood as effectively as 'boost'.